This application is a national stage of PCT International Application No. PCT/EP2008/008124, filed Sep. 25, 2008, which claims priority under 35 U.S.C. §119 to German Patent Application No. 10 2007 052 246.2, filed Nov. 2, 2007, the entire disclosure of which is herein expressly incorporated by reference.
The invention relates to an airbag safety restraint system for a motor vehicle.
Such airbags are known from the series-production of passenger motor vehicles. A main problem during the development of these airbags is to ensure maximum protection of vehicle occupants in the case of a collision of the motor vehicle, even if the passenger is for example in a poor seating position. The so-called “OoP” behavior (out of position) of the airbag in its restraint position has a great importance in such a poor seating position.
A further point which has to be considered during the development of such an airbag is avoidance to an injury of the passenger of the motor vehicle by the deployment or enlarging of the airbag itself. It is important for this that the airbag has an advantageous, so-called LRD behavior (low risk deployment).
It is thus one object of the present invention to create an airbag of the type mentioned at the outset, which achieves even better protection for the seat occupant, or which has an improved OoP behavior or LRD behavior.
This object is achieved according to the invention, by an airbag with a support structure that is displaced from a storage position to a restraint position in a mechanical manner or by means of a gas flow. A restraint volume of the airbag formed by the support structure in its restraint position is surrounded by a covering according to the invention. A characteristic of the present airbag is that at least one connection element is provided, which extends within the restraint volume, by means of which element respective components of the support structure and/or surface areas of the covering are connected to each other.
In other words, it is provided according to the invention to use an airbag which comprises a deploying support structure consisting of a plurality of hollow bodies, which are deployed by means of a gas flow, or consisting of a plurality of mechanical components.
The space which is then formed in the restraint position by the support structure—the restraint volume—is given by a covering, which can be filled either with ambient air or also with a pressurized gas. In other words, the deployment of the airbag is presently achieved by the support structure, which is enlarged by means of a corresponding gas or in a mechanical manner. The hollow bodies or the mechanical components are thereby connected to each other to a frame or a framework or the like.
If a seat occupant of a passenger motor vehicle now impacts the airbag in the course of an accident scenario, a restraint effect which is as good as possible shall be achieved. Especially, if ambient air is enclosed by the support structure or the associated covering, the restraint effect is optimized according to the invention in that the at least one connection element extending within the restraint volume is provided, which is connected to the support structure and/or the covering. This is especially important, as, at the time of the impact of the occupant on the restraint volume, its inner pressure is in principle rather lower than with conventional airbags. The inner pressure for the restraint is mainly generated by the impacting passenger himself when dislocating forward. It is thereby particularly important that this pressure build-up for the restraint takes place as efficiently as possible. This takes place according to the invention by a connection element, through which for example an uncontrolled moving away of the support structure or of the restraint volume is prevented in a reliable manner, so that the complete restraint function can be ensured.
In a further arrangement of the invention, it has additionally been shown to be advantageous if the at least one connection element extends transversely to a main deployment direction of the airbag between lateral regions of the airbag. It is especially possible in this manner to reduce a bulging of the airbag during the charge and to prevent a lateral evasion. This lateral evasion namely does not contribute to the restraint, but reduces the pressure build-up within the covering which is effective for the restraint. It is apparent that the described advantages result not only with a support structure which can be deployed with gas, but also with a mechanical solution.
An especially good restraint can be realized thereby if the at least one connection element is charged with force during the movement of the seat occupant in such a manner that a movement of the lateral regions of the airbag to the interior is achieved by the connection element. In other words, the connection element draws the lateral regions of the airbag or of the support structure together, which increases the pressure build-up within the restraint volume. The described advantages result again with a support structure which can be deployed with gas and also with a mechanical solution.
It has further been shown to be advantageous if the at least one connection element extends in a central height region of the airbag. The bulging of for example the lateral regions of the airbag can hereby namely be prevented in a particularly effective manner, so as to altogether achieve a rather concave airbag shape in the regions of the airbag seen from the exterior. This is valid with a support structure which can be deployed with gas, and also with a mechanical solution.
In a further development of the invention, the at least one connection element is formed shorter than a width of the airbag. The desired concave airbag shape is again achieved hereby, and especially a bulging of for example the lateral regions of the airbag is prevented. This is valid with a support structure which can be deployed with gas, and also with a mechanical solution.
The connection element itself can be designed differently, namely either as a strand or a rope, a strap or however preferably as a planar surface element. It is apparent that the properties of the airbag can be optimized by the specific arrangement of the connection element.
The above-described advantages are also achieved by providing a connection element, which extends within the restraint volume of the airbag, and by which the restraint volume is divided into at least two segments. It is thus possible in a simple manner to impart a different deployment and restraint characteristic to different chambers or segments of the airbag. The restraint characteristic thereby mainly concerns a different damping action per segment, which can be adjusted correspondingly. It is possible to form for example the individual segments in such a manner that the pressure present therein can for example be adjusted to the body size and/or the body regions of the seat occupants to be restrained or to the function of the respective segment. This is valid with a support structure which can be deployed with gas, and also with a mechanical solution.
It has been shown to be particularly advantageous if the segments of the restraint volume of the airbag communicate with each other via respective connections. An air or gas exchange is possible, if necessary, to adjust desired properties of the airbag. It has however to be considered within the scope of the invention that the segments or chambers can also be separated completely from each other. Holes or leakages or even valves, especially check valves, are thereby suitable as respective connections between the individual segments. Corresponding flaps or other connections known to the expert are also conceivable.
In a further arrangement of the invention, it has additionally been shown to be advantageous if the restraint volume is divided into at least two segments by means of the connection element in the vertical direction (z direction) of the airbag or of the motor vehicle. By this segmentation, the restraint can for example be adjusted at different body regions as for example the head, the chest or the like and/or different occupant sizes. It has thus to be considered that the head impacts different airbag regions with different occupant sizes. This circumstance can be accommodated by the corresponding segmentation in the vertical direction.
In a further arrangement of the invention, it has additionally been shown to be advantageous if the restraint volume is divided into at least two segments by means of the connection element in the longitudinal direction (x direction) of the airbag or of the motor vehicle. The restraint can for example be adjusted for different occupant distances to the air bag or to the supporting surface of the airbag. The segmentation can additionally be used to adapt the deployment of the airbag to different occupant distances. By the division into several segments or chambers, the completely deployed segments or chambers can build up a corresponding pressure during the restraining effect, without its gas distributing into segments which are not yet deployed, and the corresponding restraining effect being lost thereby. Such an empty volume or such a leeway, which would be caused by a non-deployed segment, would namely have an extremely negative effect on the restraining effect. A further advantage of the segmentation of the restraint volume in the longitudinal direction (x direction) is that the airbag can be adapted to different accident severities or forward dislocations of the occupant. It is thus for example conceivable, with a driver or passenger airbag, to use the chamber which is at the front in the longitudinal vehicle direction, the last chamber as an emergency brake to protect the occupant in any case from an impact on the dashboard or the steering wheel.
In a further development of the invention it is additionally possible to divide the restraint volume by means of the volume element in the transverse (y) direction of the airbag or of the motor vehicle into at least two segments. It is in particular possible to adjust the restraint for different body regions as for example the head, the chest, the arms or the like. The segmentation can be advantageous for a diagonal impact, where the outer segments dampen for example in a stronger manner than the inner segments. Not least, the occupant kinematics can be influenced during a collision of the passenger motor vehicle. The different segmentations in the vertical direction, the longitudinal direction and the transverse direction of the airbag can naturally be combined in an arbitrary manner to optimize the occupant kinematics, the force distribution and the restraining effect with regard to the occupant.
It has additionally been shown to be advantageous in a further development of the invention if at least one additional restraint volume is provided, which is arranged outside the actual or main restraint volume. While the main restraint volume namely extends essentially behind the support surface for the occupant, the additional restraint volume shall in particular be arranged laterally thereof. The additional restraint volume can initially for example thus not be directly used for the restraint of the occupant, wherein this will become usable during the further course of the accident scenario, when a corresponding movement of the airbag or of the seat occupant relative to the airbag results namely by lateral impact of for example the arms, the knees or the legs of the occupant in the course of the forward dislocation. The restraint volume can thereby have an associated covering. It is additionally conceivable to extend or enlarge the covering of the airbag or of the support structure correspondingly by the restraint volume.
It has finally been shown to be advantageous if the airbag is designed in an essentially cuboidal manner. While a conventional airbag is designed in a spherical manner, it is especially possible by means of the support structure according to the invention to obtain a cube form. It is thus for example possible to maximize the effective surface during the immersion of the seat occupant from the start. This effect can also be achieved by a shape of the airbag which is adapted to the supporting surfaces. It is thus for example possible to let the form of the airbag follow the surface of the dashboard or the passenger side.
The same is also valid for an idealized assumed and average occupant contour.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.